1. Field of the Invention
The present invention generally relates to susceptors, and more particularly to a susceptor provided as a base of a substrate in a chamber of a vacuum apparatus where a substrate fabrication process such as sputtering and thin film deposition is carried out. The present invention relates to the surface processing method of a subject to be processed such as the susceptor.
2. Description of the Background Art
In general, the cleaning process of a susceptor is carried out, not for each substrate deposition, but at the end of the deposition of a set of several substrates. Therefore, the film or coating attached to the susceptor will be layered during film deposition of the substrate.
Conventionally, the cleaning method of a susceptor that is carried out succeeding the film growth process is implemented along the flow of process shown in FIG. 7. First, an etching step (FIG. 7(A)) is carried out until the layered film attached on the susceptor during substrate film deposition is completely removed, followed by a pure water rinsing step (FIG. 7(B)), an ultra pure water rinsing step (FIG. 7(C)), a drying step (FIG. 7(D)), an inspection step (FIG. 7(E)), a packaging step (FIG. 7(F)) and the like, to follow the cycle of re-usage.
The sales of personal computers have increased drastically in accordance with the spread of the Internet. As to the specification of liquid crystal panels incorporated in such personal computers, more stringent requirements are implied with respect to higher luminance, higher accuracy, higher opening ratio, faster response, and lower power consumption. Furthermore, the necessity of improving the yield is essential since the cycle of a sudden drop in price has become shorter.
Particularly in order to accommodate higher accuracy and higher opening ratio, the line width of gates and source lines must be made smaller. In the process of fabricating a thin film transistor (TFT), reducing the number of particles during film deposition in the metal wiring formation apparatus such as the sputtering device is indispensable so as to suppress the disconnection ratio of lines.
The most general case of the source of generating contaminants and foreign objects is caused by the peeling or flaking off of films that have adhered on the walls in the chamber and on members and the like during film deposition. As to an anti-adherence plate used in a chamber as shown in FIG. 8, peeling off is generally reduced by applying a blasting process on the mother material of Al, SUS, and the like or applying Al spray on the surface.
However, there is a susceptor portion that cannot be accommodated by the aforementioned anti-adherence plate used in the chamber as shown in FIG. 8. The susceptor is the supporting portion for the substrate that must not conduct with the substrate and that must be superior in surface planarization and heat resistance. The susceptor is generally formed of glass that has SiO2 as the main component to prevent any scratches or defects on the substrate. Therefore, no prominent means has been provided as to the surface processing from the standpoint of the possibility of inducing cracking and the like.
Since the cleaning process of a susceptor is generally not carried out for each film deposition of the substrate and is performed after the film deposition of a set of several substrates, the lamination film adhering on the susceptor became the source of generating contaminants and foreign objects that peel off to fall on the substrate during the film deposition process of the substrate.
In order to satisfy the requirements as to improving the quality and facilitate reduction of the material cost, it has become necessary to prevent the generation of contaminants caused by the peeling off film from the susceptor.
Japanese Patent Laying-Open No. 10-070099 discloses a method of cleaning a semiconductor wafer subjected to sand blasting and a semiconductor wafer cleaned by this method. The method is directed to reliably removing contaminants generated by the sand blasting process by defining the processing temperature of hydrofluoric acid used for cleaning the semiconductor wafer after the sand blast process. Furthermore, the blasting process and etching process on the semiconductor itself are also taught.
However, the method of cleaning a semiconductor subjected to sand blasting disclosed in Japanese Patent Laying-Open No. 10-070099 cannot be directly applied to the case where the susceptor is formed of glass that has SiO2 as the main component since it will easily crack.
There was also the problem that the layered film adhering on the susceptor will conduct with the film grown at the end face of the substrate to cause overdischarge.
In view of the foregoing, an object of the present invention is to provide a surface processing method and cleaning method preventing generation of contaminants.
Another object of the present invention is to provide a susceptor improved so as to withstand stress of a layered film during film deposition and to prevent overdischarge caused by the laminated film adhering on the susceptor establishing conduction with the film grown at the end plane of the substrate.
According to an aspect of the present invention, a susceptor provided as a base of a substrate within a vacuum chamber of a thin film deposition apparatus includes a susceptor main unit. A stepped portion supporting the substrate from the bottom is formed on the susceptor main unit in a size smaller than the substrate.
According to another aspect of the present invention, a surface processing method includes the step of applying blasting on the surface of a susceptor that has SiO2 as a component.
According to a further aspect of the present invention, the surface processing method includes the step of masking a susceptor portion forming contact with the substrate, prior to the blasting step.
According to still another aspect of the present invention, the surface processing method includes the step of high-pressure water rinsing the surface of the susceptor, prior to the blasting step.
According to a still further aspect of the present invention, the blasting step is carried out using SiO2 or SiC.
According to yet a further aspect of the present invention, the surface processing method includes the step of high-pressure water rinsing the surface of the susceptor after the etching step.
A surface processing method according to yet another aspect of the present invention relates to a surface processing method of a glass jig that has SiO2 as the main component, used in the neighborhood of the substrate and wafer in the semiconductor formation step, plasma display panel (PDP) formation step, plasma address liquid crystal (PALC) formation step and flat panel display (FPD) formation step.
A blasting step is applied on the surface of a subject to be processed (first step). The surface of the under-processing subject is etched (second step). The under-processing subject is cleaned by the means of (i) or (ii) below.
(i) Water rinsing at high pressure.
(ii) Rinsing with pure water and rinsing at high pressure.
A surface processing method according to yet a still further aspect of the present invention relates to a surface processing method of a thin film transistor substrate (TFT substrate) of a reflective liquid crystal panel.
The surface of the TFT substrate is subjected to blasting (first step). The surface of the TFT substrate is etched (second step). The under-processing subject is cleaned by the means of (i) or (ii) below.
(i) Water rinsing at high pressure.
(ii) Rinsing with pure water and rinsing at high pressure.
According to an additional aspect of the present invention, the surface processing method further includes the step of masking a susceptor portion that forms contact with the substrate, prior to the blasting step.
According to another aspect of the present invention, the surface processing method further includes the step of rinsing the surface of the susceptor at high pressure, prior to the blasting step.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.